How To Build A Bench: Build It In An Afternoon!
Photo 5: Add the backrest
Position the backrest support on the leg assembly as shown, making sure it's at a right angle with the seat support, and mark the position on the seat support. Then drive a 3-in. screw through the middle of the backrest support into the leg brace.
Clamp the backrest support, seat support and rear leg as shown using the line as a guide. Drill a 3/8-in. hole through the center of the assembly. Drive a 3/8-in. x 5-in. bolt fitted with a washer through the hole and slightly tighten the nut against a washer on the other side.
Build the other leg assembly for the bench to mirror the first as shown. (The back support and rear leg switch sides.) Prop the stretcher 3 in. above the workbench, center it between the front and rear bench legs and screw the leg braces into the ends with two 3-in. deck screws.
Center the first 2x4 seat board over the leg assemblies and flush with the front ends of the seat supports. Screw it to the seat supports with two 3-in. deck screws spaced about 1 in. away from the edges. Line up the 2x10 with the first 2x4, space it about 5/16 in. away (the thickness of a carpenter's pencil) and screw it to the seat supports with two 3-in. deck screws. Repeat with the rear 2x4.
Rest the bottom backrest 2x4 on carpenter's pencils, holding the end flush with the seat boards, and screw it to the seat back braces. Then space and screw on the center 2x10 and the top 2x4 backrest boards.
A circular saw and a screw gun are the only power tools you really need for construction, although a power miter saw will speed things up and give you cleaner cuts. Begin by cutting the boards to length. Figure A shows you how to cut up the eight boards efficiently, leaving little waste. When you're picking out the wood at the lumberyard, choose boards that above all are flat, not twisted. That's especially important for the seat and back parts. Don't worry so much about the leg assembly 2x4s because you cut them into such short pieces that warps and twists aren't much of a concern.
After cutting the pieces to length, screw together the leg assemblies (Photos 2 – 6). It's important to use a square to keep the leg braces square to the legs (Photo 2). That way both leg assemblies will be identical and the bench won't wobble if it's put on a hard, flat surface. We spaced the leg brace 1/2 in. back from the front of the legs to create a more attractive shadow line. Then it's just a matter of connecting the leg assemblies with the stretcher (Photo 7), screwing down the seat and backrest boards, and adjusting the slopes to fit your body.